Method of making insulating-tubes.



PATENTED JULY 2, 1907.

Eu HAEFELY.

METHOD OF MAKING INSULATING TUBES.

APPLICATION FILED MAY 2, 1906.

INVENTOR WITNESSES:

ATTORNEY UNITED STATES PATENT OFFICE.

EMIL HAEFELY, OF BASEL, SWITZERLAND, ASSIGNOR TO WESTINGHOUSE ELECTRIC &

MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

Specification of Letters Patent.

Patented July 2, 190".

Original application filed September 26, 1904, Serial No. 223,442.Divided and this application filed May 2, 1906.

Serial No. 314,909-

To all whom it may concern:

Be it known that I, EMIL HAEFELY, a citizen of the Republic ofSwitzerland, and a resident of Basel, in Switzerland, have invented anew and useful Improvement in Methods of Making Insulating-Tubes, ofwhich the following is a specification, this application being adivision of my application, Serial No. 223,442, filed September 26,1904.

My invention relates to methods of manufacturing insulating tubes, andit has for its object to provide a method which may be conveniently anduniformly przu'ticed to insure the production of tubes of invariablecomposition and excellence and of great hardness and density. I

The article of nnmufaeture and the method of producing it are notdependent upon the use of specific mechanism except in the sense and tothe extent that the application of constant and substantially uniformpressure and of heat must be so made as to insure uniform producthaving'certain qualities and characteristics which will be hereinaftermore particularly pointed out, yet I have devised mechanism which I havefound admirably adapted to the practicing of my method and have setforth and claimed the same in the application of which this is adivision, a portion ofthe mechanism being illustrated in the singlefigure of the accompanying drawing, in order to enable me to set forth,with more accuracy and with better facility, the characteristic featuresof the method.

Tubes constructed in accordance with my invention comprise a pluralityof concentric layers of insulating fabric, varnish or other similarbinding material and sheet mica, or, in some cases and for somepurposes, the tubes may be formed of paper and varnish only. Thematerial which I herein designate as varnish may be any suitable gummyimpregnating and binding material which may be melted by heat to driveoff all volatile constituents as the fibrous sheet, to which it has beenapplied, passes to the prior convolution upon the mandrel.

In order to produce a tube of the desired character, a cylindrical metalcore is employed the diameter of which corresponds to the internaldiameter of the tube to be produced, and the paper, coated uniformlyupon one side with varnish, and with or without sheets of mica placedupon the coated side, is wound, under suitable tension, around the metalcore, and during such Winding operation, uniform pressure is applied,preferably along three lines throughout the length of the tube and ofsuch degree as to not only force the consecutive layers of material intosuch intimate contact as to provide a resulting product of substantiallyuniform composition, but so as to also expel all surplus varnish. Duringthe winding operation, a considerable degree of heat isalso applied toone or more of the surfaces between which the material is compressed andalso, preferably, to the material just before it reaches such surfaces,in order to melt the varnish and expel all air-and volatile constituentstherefrom and thus insure a uniform product having no impurities ordefects, and, therefore, one which will resist, at all points, themaximum difference of potential which may be resisted at any one pointin the tube.

A roll 'V of paper or other insulating fabric is supported in suitablebearings on a machine frame A and the paper p is drawn therefrom over atension roll g, around a guideroll it, and over an inclined table 1',where a coat of varnish may be applied. The coated paper from the tablef over a metal portion I of the frame to a mandrel or core a, aroundwhich it is wound by rotating the mandrel or core by machinery or byhand, the sheets of mica m, if such are employed, being introducedpreferably as the coated sheet of paper passes to the mandrel.

The mandrel is supported by a mandrel holder 0, here shown as providedwith a plurality of longitudinal recesses of angular or V-shape in crosssection, the holder being hollow and containing in its interior a gaspipe d having small outlets for the gas to be burned for the purpose ofheating the holder and also the portion I of the frame.

The air for supporting combustion may enter the holder and the productsof combustion may pass out from it by means of passages c, the passagesat the lower side of the holder serving for the first named purpose andthose at the upper side for the purpose last named.

The constant and substantially uniform pressure which it is necessary toexert upon the material as the tube is in process of formation isprovided by means of a pressure device comprising a horizontal bar t anda pressure roller f having flanges or ribs F each of which has a beveledouter edgeand one of which rests upon the upper side of the roll as itis formed by the rotation of the mandrel. Since the pressure device isloosely supported upon the roll and the recess in the mandrel holder isof angular shape in cross section, the pressure is uniformly appliedalong three lines which are approxi mately 120 apart and neither thedegree of pressure nor the linesalong which it is applied varymaterially as the diameter of the tube increases.

As I have already stated, any excess of varnish over that which isrequired to bind the layers of paper or the layers of paper and micainto intimate contact and to fill all interstices in the material willbe expelled adjacent to the inner edge of the frame-portion I and may beremoved at intervals, by any suitable means, as the same accumulates. Idesire to also state again that the form and relative location of theparts for the purpose of securing the desired pressure and theapplication of heat'to the material may be reversed and otherwisemodified as to form, dimensions and relative arrangement, withoutmaterially affecting my present invention, so long as the application ofheat and pressure is such as to insure the production of tubes-havingthe qualities and characteristics which pertain to those manufactured bythe use of the mechanism here illustrated and by the method described.

I claim as my invention:

1 The method of making an insulating tube which consists in winding :1varnish-coated fabric upon a mandrel to form a plurality of layers andapplying heat to the uncoated surface of the fabric as it approaches themandrel and substantially uniform pressure and heat to the outer surfaceof the tube during the winding operation.

2. The method of making an insulating tube which consists in winding avarnish-coated sheet of fibrous material upon a mandrel andsimultaneously applying heat to the material as it approaches themandrel, and both heat and substantially uniform pressure to the tubeduring the winding operation.

3. -The method of making an insulating tube which consists in winding aplurality of insulating sheets and interposed gummy material upon ampndrel and applying heat externally to the outer sheet as it passes tothe mandrel and heat and a substantially uniform, continuous pressure tothe outer surface of the ube as it is formed.

4. The method of making an insulating tube which consists in winding 9.sheet of varnish-coated fibrous material and a superposed layer of micaupon a mandrel and simultaneously pressing the tube against a pluralityof heated surfaces with continuous and substantially uniform forceduring the winding operation.

5. The method of making an insulating tube which consists in winding avarnish-coated fabric upon a mandrel to form a plurality of convolutionsand simultaneously pressing the successive outer convolutions against aplurality of heated surfaces with substantially uniform continuousforce.

In testimony whereof, I have hereunto subscribed my name this th day ofApril, 1906.

Witnesses:

WESLEY G. CARR, BmNnY HINES.

